1. Field of the Invention
The invention relates to a laryngeal-mask construction, and in particular, to a laryngeal-mask construction characterized in that it has simple elements, is easy to assemble, and keeps a necessary bending curvature such that it can stick closer to the larynx of a patient. It also has an integrated internal element that supports the mask resulting in better sealing so that it can not only prevent leakage of respiratory gas but also can prevent insufflations into the esophagus. An additional element is incorporated inside the hollow cavity of the mask so that any gastric fluid would be contained and adsorbed if there is regurgitation unfortunately. It is suitable to use to establish airway in a patient that is anesthetized or to be anesthetized, and can be substitute for a facemask for breathing in a first aid.
2. Description of the Prior Art
The inventor of this application had disclosed a laryngeal-mask construction in U.S. Pat. No. 6,546,931, titled “A supraglottic airway structure specifically used for anesthesia”, such as shown in FIG. 9, including a silicone mask B and a main tube seat A with diverging tube opening A1. The main tube seat A is fitted through the silicone mask B. The upper and lower faces of the silicone mask B are formed with perforations B1, B2. A rubber annular tube F having different diameters is implanted in the silicone mask at the equator thereof. A soft sleeve C is fitted on the silicone mask B. The inner diameter of the soft sleeve C corresponds to the profile of the main tube seat A. The soft sleeve C has an irregular profile corresponding to the configuration of inner side of the fauces. The soft sleeve C is pushed forward to make an upper tube opening of the main tube seat A protruding out of the soft sleeve C. An anesthetic gas intake tube E having an engaging flange is fitted through the diverging section of the main tube seat A and engaged therewith. A fine string D is used to tie up the soft sleeve C, main tube seat A and the intake tube E so as to prevent the soft sleeve C from detaching from the main tube seat A. The laryngeal mask is able to completely air-tightly seal the throat of a patient without leakage and over-compressing the mucous membrane of the throat.
Although the construction described above could achieve the purpose of an airway conduit, it has the following operational and structural disadvantages:
When the above mentioned supraglottic airway device is placed in the oral cavity of a patient, it tended to be folded back due to contact of the front edge of the laryngeal-mask with the posterior wall of the pharynx.
The above-mentioned device has a circular opening that tends to increase the difficulty in the alignment with trachea as it is inserted into the oral cavity of a patient.    1. Because the mask body in the above-mentioned device is supported by an elliptical solid tube, as the mask body is inserted into the pharyngeal cavity of a patient, its periphery will be in a position against the two tonsils on both sides of the patient's pharyngeal cavity, thereby as the device is moved forward or is removed, not only there will be increased discomfort to the patient, but also the rubber annular tube of the device could be deformed, and further, due to the asymmetric organization of the tonsils, pharyngeal muscle, and the like in the pharynx, the front end of the device will shift from the center position of the larynx.    2. When the device is inserted into the oral cavity of a patient, its mask body will contact with the protruded epiglottis of the patient, and might hurt the epiglottis as the mask body moves forth and back. In addition, the epiglottis tends to block up the front outlet of the tube, resulting into the blockage of the airway.    3. In the actual practice, although the tip of the mask body can be placed against the esophagus of the patient, due to the mostly asymmetrical anatomy of the patient and the deviation during insertion, even if the laryngeal mask can be inserted into a right destined position (i.e., the center of the larynx), it might be unable to stick tightly around the opening of the esophagus, resulting into the escape of the gas into the esophagus and the stomach during positive pressure breathing. Furthermore, the annular ring can support only the side walls of the mask. Without covering completely the anterior wall of esophageal sphincter, it is inadequate in preventing gastric insufflations or aspiration.    4. The above-mentioned device has a number of constitutional elements, and its assembly is cumbersome. Moreover, when it is combined with an auxiliary device for assisting the bending of the tube body, no place is provided for the stopping of the inserted auxiliary device, whereby the larynx is susceptible to injury if the auxiliary device protruded out of the mask body.
A construction disclosed in the U.S. Pat. No. 5,355,879 provided a laryngeal mask construction to achieve the purpose of loading the peripheral-cuff seal to the laryngeal inlet; however, it had limitation for the airway tube to get closer enough because of the intervening peripheral cuff. It might also increase the pressure at the back wall of the pharynx. Further, in a laryngeal mask construction disclosed in U.S. Pat. No. 5,878,745, a gastro-laryngeal mask features pliantly compliant construction of the distal half of the mask, wherein the mask is of generally elliptical configuration, with an inflatable peripheral cuff to seal and support the mask around the laryngeal inlet. A back cushion is inflatable to engage the back wall of the pharynx and thus to forwardly load the peripheral-cuff seal to the laryngeal inlet. An evacuation tube for external removal of a possible gastric discharge completes an evacuation or discharge passage contained within the mask and opening through the distal end of the peripheral cuff. Special provision is made for assuring integrity of the discharge passage within the flexible distal half of the mask, i.e., assuring against collapse of the distal-end half of the pliantly compliant evacuation tube in the distal region of the mask, such that inflation of the mask does not compromise viability of the evacuation tube by compressing pliantly compliant material of the evacuation tube during periods of mask inflation. The special provision also favors such collapse of the mask when deflated as to provide a leading flexible edge for piloting a safe and correct advancing insertional advance of the deflated mask in the patient's throat, in avoidance of epiglottis interference and to the point of locating engagement in the upper sphincter of the oesophagus.
The above-mentioned evacuation tube for external removal of a possible gastric regurgitation fluid was effective only when the distal mask tip is engaged tightly in the upper sphincter of the esophagus, which might not be the case in some patients. The evacuation tube was also too small that if there were any particulate materials in the regurgitation, it would block the tube and defeats its mechanism.
Moreover, this sort of construction is supposed to be used only in fasted patients whose gastric fluid will not exceed 50 ml. It needs only a mechanism to accommodate the less than 50 ml of possible regurgitation fluid in the mask body and to adsorb it so that it will not aspirate into the laryngeal inlet causing laryngeal spasm or damage to the lung.
Accordingly, in view of the foregoing deficiencies associated with the previous constructions, the inventor had devoted to improve it, and finally, after several trials and errors, has provided a laryngeal-mask construction characterized in that it has simple elements, is easy to assemble, and can maintain a desired bending curvature in its use such that it can stick closer to the larynx of a patient with better seal and less risk of aspiration.